The present invention is a system for delivering dry, compressed air to a plant air system with increased efficiency.
In the past, it has been common to provide compressed air for plant air systems by compressing atmospheric air, directing the compressed air through an after-cooler which removes large amounts of moisture. The moisture is removed by a heat exchange system having cooling water from a cooling tower, used in connection with the after-cooling equipment, to cool the heated compressed air and condense moisture into a separator and drain. However, it is desirable to remove moisture prior to compression to save air compressor power by the reduction in volume of air at compressor inlet caused by cooling and removal of moisture. There is also a reduction in the discharge temperature on single stage compressors. In addition, the use of dry plant air in a plant air system reduces maintenance costs and wet air problems, such as caused by the condensation in the air operated equipment.
In my prior U.S. Pat. No. 3,034,315, I removed the moisture primarily by pre-cooling and pre-drying so that the hot compressed air entering the air lines results in an increase in air volume and a substantial savings in power and water. Pre-cooling requires low temperatures for adequate moisture removal, introducing the problem of freezing in cold weather, and can cause pulsation of the compressor intake to cause unwanted vibrations and noise. These problems were dealt with in the above patent. In my prior U.S. Pat. No. 2,632,315, a system for delivering dry, compressed air at higher efficiencies also cooled the intake air prior to delivery to the compressor and in part, from the delivery of the compressed air to the compressed air lines in a heated condition. Other air conditioning systems can be seen in my prior U.S. Pat. No. 3,015,216 for an air conditioning system, and U.S. Pat. No. 2,984,082 for an air conditioning system, and U.S. Pat. No. 2,939,296 for an air cooling system, and U.S. Pat. No. 2,773,356 for an air cooling system with recirculating passageway.
Aside from my prior patents, the prior art typically uses intake filters for preventing dust and dirt being drawn into the compressors, and to eliminate wear in the cylinders and pistons and to prevent carbonization of the compressor valves. The prior art further uses after-coolers to remove the moisture and oil condensed from the air to prevent troublesome condensation in the pipe lines. Cooling water pumps are used in prior art systems for circulating the cooling water for the after-coolers, along with cooling refrigeration systems, and finally, moisture separators have been commonly used for the separation of mist and entrained liquids from the air system.
In contrast to the prior art, the present invention deals with improvements to my prior patents, and especially to improving the efficiency of the operation of an air conditioning system for delivering dry heated air to a plant air system.